Press

ABSTRACT

A press which is adapted to be extended in lateral and vertical dimension and arranged so that the reaction forces developed during pressing and parting are developed within the system of actuators and platens, i.e. essentially within the actuator cylinders; in one form the actuators are peripherally arranged with the upper platen supported on the piston rods; there is also disclosed a press having first and second actuator means arranged to operate in series and sequentially, the first operating means being for example a mechanical lifting device, the press being adapted to operate where the distance of draw is greater than the stroke of the hydraulic actuators.

United States Patent 1w:

Cadogan-Rawlinson et al.

l l PRESS {76] Inventors: Christopher Robert Johnston Cadogan-Rawlinson, Ex-Press Plastics Ltd. Harlcston, Norfolk. John Ross Kinley, The Manse. Wortwcll. Norfolk. both of England [22] Filed: June 2|, i973 [2|] Appl. No.: 372,302

Related U.S. Application Data I63] Continuation of Ser. No. 270.056. July It). W72 abandoned. which is a continuation of Ser. No. 877.8]0. Nov. l8. I969. abandoned,

[30] Foreign Application Priority Data Nov. l9. 1968 United Kingdom 54927/68 152] US. Cl. 425/135; 425/ I36; 425/l56;

[56] References Cited UNITED STATES PATENTS 2.792.592 5/l957 McGee 425/406 1451 Nov. 18, 1975 Primurv E.\'umirwrRobert L. Spicer. Jr.

[57] ABSTRACT A press which is adapted to be extended in lateral and vertical dimension and arranged so that the reaction forces developed during pressing and parting are developcd within the system of actuators and platens. i.e. essentially within the actuator cylinders; in one form the actuators are peripherally arranged with the upper platen supported on the piston rods; there is also disclosed a press having first and second actuator means arranged to operate in series and sequentially, the first operating means being for example a mechanical lifting device. the press being adapted to operate where the distance of draw is greater than the stroke of the hydraulic actuators.

I0 Claims, 7 Drawing Figures US. Patent Nov. 18, 1975 Sheet2of5 3,920,364

U.S. Patent Nov. 18, 1975 Sheet 3 of5 3,920,364

cam/J T0 B91154 J. GMQMA W/Ws /x J IM A. KIA/LE7 US. Patent Nov. 18, 1975 Sheet4of5 3,920,364

J KIA/LET US. Patent Nov. 18,1975 heets of5 3,920,364

FIGS

TIT T 20 1 (Ll 0 7261 6X :6 i @D LM- QW/NM Joli/V Kl/V/ El PRESS This is a continuation of application Serial No. 270,056, filed July 10, I972, now abandoned, which is a continuation of Ser. No. 877,810 filed on Nov. I8, I969, now abandoned.

The present invention relates to an improved press, particularly but not exclusively suitable for cold-pressing reinforced plastics articles.

Conventional presses have an actuator mounted to a frame bolted to the floor and arranged in a central position with the p? :ton attached to the upper press or mould platen, the lower platen being supported on the floor or with the actuator on the floor lifting the lower platen; the upper platen being rigidly mounted on top. In either such arrangement the hydraulic fluid acts on the large area side of the piston, i.e. the side having no piston rod, and the frame is necessary to provide the reaction structure against which the hydraulic fluid acts.

In this kind of press the presence of the reaction frame renders horizontal extension of the platens or press impossible and severely limits vertical extension. Also in this kind of machine great difficulty is often experienced in building the larger sizes of platen with rigidity to withstand the thrust of the ram applied centrally, without flexing.

The press can therefore readily be extended in vertical stroke and sideways. Two or more actuators are preferably provided at peripheral regions of the press, the actuators being synchronised and arranged preferably so that one of the platens is attached to the piston rods and the other is attached to the bodies of the cylinders. It is normally more convenient to attach the cylinders to the base platen and to support the upper platen on the piston rods, but the converse arrangement in which the piston rods are fixed to the base platen and the cylinders fixed to the upper platen, is a possible altemative.

In this form of press there is no reaction frame, the only connection between the platens being normally via the piston rods. However slide rods may be provided as additional guiding means for the upper platen if desired. These are not normally necessary but may be used, e.g. in combination with a double acting actuator independently mounted on the floor and the pistons of which are arranged to press against the platens directly or through intervening tied levers.

While two or more actuators will normally be used in a balanced distribution for each movable platen component, it is sometimes possible to use only one actuator at an edge region of the press, where the articles are of small area. A slide rod may be arranged opposite the piston for guidance of the movable platen.

The invention also includes a press comprising a pair of platens or equivalent members adapted to be brought together for pressing over a working area and actuating means for bringing together and parting the members and including first and second actuating means arranged to operate in series and sequentially, the first actuating means operating to bring the mould members to a proximity within the maximum stroke of the second actuating means and the second actuating means operating thereafter to complete the pressing.

In the accompanying drawings:

FIG. I is an isometric view of a conventional press,

FIGS. 2 and 3 are isometric views of two preferred presses in accordance with the invention,

FIG. 4 is an isometric view of a third embodiment,

FIG. 5 is a cross-sectional view of another form of press in the open position,

FIG. 6 is a similar view of the press of FIG. 5 in the closed position, and

FIG. 7 is an enlarged sectional view of part of the press of FIG. 5 showing the ram connecting means.

Referring to FIG. I there is shown a conventional press which may be for hot-moulding or cold-moulding reinforced plastics, comprising a base platen 10 supported from the floor on base I], a roof element 12 rigidly fixed to the base platen 10 by slide rods 13 which serve as tie rods, taking the strain of the reaction to movement of the piston. Slidingly mounted on the slide rods 13 is an upper, movable platen 14. The top of the platen 14 is connected to the end of the piston rod 15 of the actuator 17, the cylinder 17 of which is fixed centrally to the roof element 12. It is evident in the form of construction that the slide rods 13 and roof element l2 constitute a reaction frame and this frame inhibits the extension of the press either vertically or horizontally.

The direction of fluid pressure in the cylinder is shown by the full line arrow and the reaction provided by the frame is shown by the dotted arrow.

FIG. 2 shows a similar press in accordance with the invention. In this case there are three pairs of actuators 12a and 12b arranged along the length of the rectangular base platen 10 which has bench legs 11'. FIG. 3 shows a press with only two pairs of actuators, in this case mounted in the inverse position on top of the upper movable platen. It will become evident that any number of actuators may be employed, in either position, so long as they are in a balanced formation so that the pressure is evenly distributed, and are synchronised.

In FIG. 2, the upper platen 14 (or each of its component parts) is mounted to the ends of the piston rods 15a, 15b and has no other support or guide. In the case of presses for cold-moulding adapted to exert a pressure in the region of 15 to 20 psi, or 40 to 50 psi on parting, suitable actuators are available having glands 18 of about 4 inches in length and these together with the pistons and rigid attachment of the rod ends provide sufficient guidance for the piston rods and upper platen. No special considerations are required in synchronising the actuators. Against expectation it has been found that it is possible to synchronise two or more actuators only by paying strict attention to the construction and alignment of the mechanical elements and to the hydrodynamic balance of the various circuits involved.

In particular it is necessary for optimum operation for the hydrodynamic resistivity of each circuit, both on flow and return, to be exactly equated. This must embrace all components in each circuit, e.g. the pressure and displacement of pumps, valves, and in the case of solenoid operation, time scale response, pipe work, bends and joints. The breakaway pressures of each cylinder should be of equal value and this pressure should not exceed one third of the total pressure required to overcome the initial inertia of the complete moving platen assembly.

In the presses of FIGS. 2 and 3 the direction of the fluid pressure for moulding is shown by the arrow. There is no reaction pressure acting against any part of the press, since in the arrangement shown the reaction forces are developed in the cylinder itself, between its ends.

It will be noted that in contrast to the arrangement of FIG. 1, the smaller area of piston, i.e. the side with the piston rod is used for applying the moulding pressure. This has been found to be an advantage rather than a disadvantage, because more pressure is required, in cold press moulding at least, to break the mould open against the generated vacuum than in the operation of moulding, and the required thrust differential is in this case conveniently provided by selecting a combination of ram and annulus areas with the required ratio. Otherwise in providing sufficient parting thrust on the annulus side of the ram the closing thrust is unavoidably increased well beyond that needed for the process and further increases the size of platen necessary to prevent bending. Alternatively, supplementary parting rams have to be employed. This is the case with the press of FIG. I.

The presses of FIGS. 2 and 3 may readily be extended in daylight by screwing in extension sections of piston rod. This is not possible of course where a frame is used as in FIG. 1. Similarly the press of FIGS. 2 and 3 can be expanded in the direction of its narrow horizontal dimension by drawing a second press against the side of the first press and locking the platens together and synchronising the actuators. Any number of presses can be added in this way. It is less easy to extend the press in the other horizontal dimension but it is nevertheless considerably easier than when a frame is present as in FIG. 1.

FIG. 3 shows the converse arrangement of cylinders and piston rods to FIG. 2 and is within the scope of the invention. In this arrangement the cylinders are mounted to the upper platen and move with the platen, while the piston rods are attached to the base platen and are immovable.

This is the arrangement of choice in long stroke applications where cylinders mounted on the bottom platen could require excavation of the floor.

FIG. 4 shows a modification of a press module in which only one actuator is used, a slide rod 40 being provided opposite the actuator for stability and to ensure correct location of the platens during pressing. A couple actuator may be used in a control position with pairs of formers symmetrically arranged around it. In such a case, such rods need not be used.

FIGS. 5, 6 and 7 illustrate a press arranged as in FIG. 3 and also modified to take an abnormally deep die and fonner which would, in an unmodified press require actuators of very large stroke to accomodate the depth of draw. In this embodiment the upper former 24 is supported by the cross members 25 of a gantry movable by means of a jack which may comprise a secondary hydraulic actuator, cables or acme screw jacks 23 as shown. Any kind of power or hand operated vertically movable gantry may be used. The cylinders of the actuators 22a, 22b are mounted to the cross members 25 with the ram ends pointing downwards. Any number of pairs of actuators, cross members and jacking or guiding uprights may be distributed along the bed 21 depending upon the length of the press.

In operation, the upper former 24 is lowered to an operating position within the depth of draw of the die and former when plugs 26 at the ends of the rams engage and lock with latches provided in extensions 27 of the lower former which is freely supported on a bed 21'. The latching means and control means are shown in FIG. 7. The plugs 26 enter a socket 28 in each exten' sion 27 and one of them (shown) actuates a microswitch 29 in the socket. This energises a pneumatic actuator 30 which causes a U-shaped latch to slide forward around a restricted neck 31 on the plug and locl\ the plug against shoulders 32, 33 at the entry to the socket.

The microswitch also energises the main hydraulic actuators 22a, 22b, brings the jacks to a halt, and starts a timer T which reverses the various operations at the end of the pressing period and resets the mechanism for the next molding operation.

The main actuators (22a & 22b) lift the lower former off its bed or cradle 21' into pressing engagement with the upper former, correct location being ensured by cooperating pins 34 and sockets 35. At the end of the pressing period the actuators 22a, 22b press the lower former away.

It will be evident that the gantry does not act as a reaction frame as in the known press of FIG. I. The uprights do not move during pressing or parting they take the additional weight of the lower former, which may, if necessary, be counterbalanced.

In this arrangement both horizontal axes and the vertical axis are capable of infinite extension.

The press of the invention may be used for coldmoulding reinforced plastics articles, e.g. by the method described in my co-pending British Patent application No. 59746/68, and the invention includes a method of cold-mouldin g articles of reinforced plastics comprising inserting the material to be moulded between formers attached to or constituting the platens or equivalent members of a press of the invention and operating the press.

We claim:

1. A molding press comprising support frame means a pair of opposed press members vertically movable relative to each other with said supporting means for pressing and parting coaction, synchronously acting actuators for commonly effecting pressing and parting coaction of said press members, said actuators being individually spaced apart and independently disposed with respect to each other and arranged in balanced relationship to each other, and said actuators further being interposed substantially peripherally of said press members and arranged to individually operatively interconnect said press members in common directional internal force-bearing relation and collectively constitute a portion of the supporting frame which operatively interconnects said press members during pressing and parting coaction of said press members.

2. Press according to claim 1 wherein the press is in the form of a basic interlocking unit adapted as a module with locking means for accretion by modular addition for extension peripherally in any horizontal direction.

3. Press according to claim 1 wherein said actuators include pistons.

4. Press according to claim 1 wherein said actuators include pistons and cylinders for driving said pistons.

5. Press according to claim 1 wherein said actuators include plug-end means arranged to fixedly interconnect said press members.

6. Press according to claim I wherein said actuators include plug-end means arranged to releasably lockingly interconnect said press members.

7. A molding press comprising a pair of opposed press members vertically movable relative to each other for pressing and parting coaction, stationary upright means, vertically adjustable press member support means operatively connected to said upright means for adjusting the vertical disposition of said support means with respect to said upright means, a first of said pair of press members being suspended from said support means above the second of said pair of press members, said second press member being normally freely disposed in a rest position and said first press member upon adjustment of said support means being vertically moved from a non-operating position remote from said second press member to an operating position proximate to said second press member, synchronously acting actuators for commonly effecting pressing and parting coaction of said press members, said actuators being individually spaced apart and independently disposed with respect to each other and arranged in balanced relationship to each other, and said actuators further being interposed substantially peripherally of said press members and arranged to individually operatively interconnect said press members in common directional internal forcebearing relation and collectively constitute the supporting frame operatively interconnecting said press members during pressing and parting coaction of said press members, and releasable locking means to correspondingly interconnect said opposed press members via said actuators when said first press member is moved to operating position and disconnect said opposed press members via said actuators when said first press member is moved to non-operating position, said actuators when operatively interconnecting said press members being actuable to raise said second press member from said rest position into pressing contact with said first press memher.

8. Press according to claim 7 wherein said upright means and support means comprise a mechanical lift- 6 ing device and said actuators are fluid pressure actuators.

9. Press according to claim 7 wherein said actuators are fluid pressure actuators each including a cylinder and a piston, each said cylinder being correspondingly connected to one of said pair of press members, said releasable locking means each includes a first locking part disposed on each corresponding piston and a second locking part disposed on the other of said pair of press members and cooperating with the first locking part to correspondingly lockingly interconnect said press members via said pistons and cylinders when said first press member is moved to operating position and disconnect said press members via said pistons and cylinders when said first press member is moved to nonoperating position, means for locating the press members in alignment when said second press member is raised from said rest position into pressing contact with said first press member, and means for effecting the disconnection of said locking parts at the end of a pressing and parting coaction sequence.

10. Press according to claim 9 wherein said second locking part includes latch means, latch actuating means for engaging said latch means to operatively lock said locking parts, automatic control means for positioning said first and second locking parts prior to their locking, means for operatively adjusting the vertical disposition of said support means with respect to said upright means, means for stopping the operation of said means for adjusting the vertical disposition of said support means and for energizing said actuators for pressing, a timer including means for energizing said actuators to effect parting of said press members and to release said latch actuating means and to start the operation of said means for adjusting the vertical disposition of said support means to move said first press member to non-operating position, and means for resetting said control means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, D d November 18,

Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, between lines 28 and 29 insert the paragraph:

- The invention includes a press comprising a pair of vertically seperable platens or equivalent members adapted to be brought towards one another and apart by one or more fluid actuators to effect pressing, characterised in that the actuator(s] are peripherally mounted with the piston rod(s) extending vertically between the platens or equivalent members and so arranged that the reaction forces developed during pressing and parting are developed within the system of actuator(s) and platens or equivalent members, no reaction frame being necessary.

Signed and Scaled this Eighth Day of March 1977 [SEAL] Arrest:

RUTI'I C. MASON C. MARSHALL DANN 8 H Commissioner nfParenrs and Trademarks Christopher Robert Johnston Cadogan-Rawlinson etal 

1. A molding press comprising support frame means a pair of opposed press members vertically movable relative to each other with said supporting means for pressing and parting coaction, synchronously acting actuators for commonly effecting pressing and parting coaction of said press members, said actuators being individually spaced apart and independently disposed with respect to each other and arranged in balanced relationship to each other, and said actuators further being interposed substantially peripherally of said press members and arranged to individually operatively interconnect said press members in common directional internal force-bearing relation and collectively constitute a portion of the supporting frame which operatively interconnects said press members during pressing and parting coaction of said press members.
 2. Press according to claim 1 wherein the press is in the form of a basic interlocking unit adapted as a module with locking means for accretion by modular addition for extension peripherally in any horizontal direction.
 3. Press according to claim 1 wherein said actuators include pistons.
 4. Press according to claim 1 wherein said actuators include pistons and cylinders for driving said pistons.
 5. Press according to claim 1 wherein said actuators include plug-end means arranged to fixedly interconnect said press members.
 6. Press according to claim 1 wherein said actuators include plug-end means arranged to releasably lockingly interconnect said press members.
 7. A molding press comprising a pair of opposed press members vertically movable relative to each other for pressing and parting coaction, stationary upright means, vertically adjustable press member support means operatively connected to said upright means for adjusting the vertical disposition of said support means with respect to said upright means, a first of said pair of press members being suspended from said support means above the second of said pair of press members, said second press member being normally freely disposed in a rest position and said first press member upon adjustment of said support means being vertically moved from a non-operating position remote from said second press member to an operating position proximate to sAid second press member, synchronously acting actuators for commonly effecting pressing and parting coaction of said press members, said actuators being individually spaced apart and independently disposed with respect to each other and arranged in balanced relationship to each other, and said actuators further being interposed substantially peripherally of said press members and arranged to individually operatively interconnect said press members in common directional internal force-bearing relation and collectively constitute the supporting frame operatively interconnecting said press members during pressing and parting coaction of said press members, and releasable locking means to correspondingly interconnect said opposed press members via said actuators when said first press member is moved to operating position and disconnect said opposed press members via said actuators when said first press member is moved to non-operating position, said actuators when operatively interconnecting said press members being actuable to raise said second press member from said rest position into pressing contact with said first press member.
 8. Press according to claim 7 wherein said upright means and support means comprise a mechanical lifting device and said actuators are fluid pressure actuators.
 9. Press according to claim 7 wherein said actuators are fluid pressure actuators each including a cylinder and a piston, each said cylinder being correspondingly connected to one of said pair of press members, said releasable locking means each includes a first locking part disposed on each corresponding piston and a second locking part disposed on the other of said pair of press members and cooperating with the first locking part to correspondingly lockingly interconnect said press members via said pistons and cylinders when said first press member is moved to operating position and disconnect said press members via said pistons and cylinders when said first press member is moved to non-operating position, means for locating the press members in alignment when said second press member is raised from said rest position into pressing contact with said first press member, and means for effecting the disconnection of said locking parts at the end of a pressing and parting coaction sequence.
 10. Press according to claim 9 wherein said second locking part includes latch means, latch actuating means for engaging said latch means to operatively lock said locking parts, automatic control means for positioning said first and second locking parts prior to their locking, means for operatively adjusting the vertical disposition of said support means with respect to said upright means, means for stopping the operation of said means for adjusting the vertical disposition of said support means and for energizing said actuators for pressing, a timer including means for energizing said actuators to effect parting of said press members and to release said latch actuating means and to start the operation of said means for adjusting the vertical disposition of said support means to move said first press member to non-operating position, and means for resetting said control means. 